The abandoned andesite quarries in İzmir, Bayraklı, Çiçek district remains in the settlement area at present time. Stability problems occur in andesites with various weathering grades due to the increasing pore pressure and weathering grade. In this study, it was aimed to investigate the relationships between the microcrack length, especially the number of microcrack measurements on thin sections, and the weathering grade. To date, studies on weathering grade determination with microcrack measurements either on the thin section or scanning electron microscope images have been performed. However, in most of the previous studies, the method that based on Euclidian distance (linear distance between two points) equation was utilized to measure the microcrack length. Indeed, the microcracks are barely linear and they present mostly rough lines on the surface. For the reason, the microcracks in slightly, moderately, and highly weathered andesite samples were measured with high precision and a realistic approach by digitizing them via computer software in cartesian object length computation. It was determined that the length of the microcracks has a positive and significant correlation with the weathering grade. It was revealed that the orientations of microcracks effect the number of microcracks that measured along horizontal and vertical traverses and the difference between two traverses increases with the increasing weathering grade.